This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-054948, filed Feb. 29, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a traffic density analysis apparatus for analyzing the traffic density from a video image.
To detect vehicles from a video image and analyze the traffic density, generally, a change in pixel values in a video screen must be checked. However, such processing related to pixel values requires a large calculation amount. For example, for CIF format often used in ITU-T H.261, H.263, ISO/IEC MPEG-4 or the like, processing must be performed for 352xc3x97288 pixels, i.e., a total of 101,376 pixels. For such processing with a large calculation amount, dedicated hardware must be prepared, resulting in a serious problem of cost.
As described above, the prior art requires a very large calculation amount to analyze the traffic density by detecting vehicles from a video image.
It is an object of the present invention to provide a traffic density analysis apparatus based on an encoded video, which can perform high-speed stable analysis.
According to the present invention, there is provided a traffic density analysis apparatus based on an encoded video, which stably executes analysis at a high speed with a small calculation amount by narrowing down a region to undergo traffic density analysis processing using a video encoding/decoding technique.
According to the present invention, there is provided a traffic density analysis apparatus comprising a video decoder section which decodes video encoded data obtained by encoding a video signal corresponding to an analysis region and outputs a decoded video signal, and an analyzer section which sets a specific region in a screen for the decoded video signal output from the video decoder section and analyzes a traffic density in the analysis region from information related to a moving object which passes through the specific region.
In the analyzer section, for example, it is determined, whether each of predetermined blocks is a moving object, from information contained in the video encoded data and pieces of information of current and previous frames of the decoded video signal. Image analysis is performed for the decoded video signal in a block determined as a moving object, thereby acquiring object information related to setting of the specific region and the moving object.
More specifically, in the analyzer section, for example, the traffic density is estimated using the average velocity and number of moving objects which pass through the specific region as the information related to the moving object which passes through the specific region.
According to the present invention, there is also provided a traffic density analysis apparatus comprising a video encoder section which encodes a video signal corresponding to an analysis region and outputs video encoded data, and an analyzer section which sets a specific region in a screen for a local decoded signal generated by the video encoder section and analyzes a traffic density in the analysis region from information related to a moving object which passes through the specific region.
The analyzer section determines whether each of predetermined blocks is a moving object from information contained in the video encoded data and pieces of information of current and previous frames of the local decoded signal, and performs image analysis for the local decoded signal in a block determined as a moving object, thereby acquiring object information related to setting of the specific region and the moving object.
In this analyzer section as well, for example, the traffic density is estimated using the average velocity and the number of moving objects which pass through the specific region as the information related to the moving object which passes through the specific region.
As described above, in the traffic density analysis apparatus of the present invention, the traffic density can be stably analyzed at a high speed with a small calculation amount by narrowing down a region to undergo actual traffic density analysis processing to a specific region using information generated by the video decoding apparatus or video encoding apparatus.